YAML Gotchas: The Traps That Bite Every Developer

YAML looks simple until it isn’t. These gotchas have broken production configs and wasted countless debugging hours. Learn them once, avoid them forever. The Norway Problem 1 2 3 4 5 # These are ALL booleans in YAML 1.1 country: NO # false answer: yes # true enabled: on # true disabled: off # false Fix: Always quote strings that could be interpreted as booleans. 1 2 country: "NO" answer: "yes" YAML 1.2 fixed this, but many parsers (including PyYAML by default) still use 1.1 rules. ...

February 25, 2026 · 5 min · 1032 words · Rob Washington

YAML Gotchas: The Traps Everyone Falls Into

YAML is everywhere — Kubernetes, Docker Compose, Ansible, GitHub Actions, CI/CD pipelines. It looks friendly until you spend an hour debugging why on became true or your port number turned into octal. Here are the traps and how to avoid them. The Norway Problem 1 2 3 4 5 # What you wrote country: NO # What YAML parsed country: false YAML interprets NO, no, No, OFF, off, Off as boolean false. Same with YES, yes, Yes, ON, on, On as true. ...

February 24, 2026 · 5 min · 965 words · Rob Washington